Abstract

The crystallization behavior of Al and its alloys has been extensively investigated due to the importance of these structural materials. In this study, valence electron energy-loss spectroscopy in a transmission electron microscope was used to study changes that occur in the volume plasmon energy, and hence, the valence electron density, during heating and cooling through the melting temperature in submicron Al particles. The results show that a phonon anharmonicity causes a nonlinear change in the volume plasmon energy that is not present in the liquid phase after melting. The plasmon energy/valence electron density during supercooling is not a direct extrapolation from the liquid state and tends to stabilize, possibly due to local ordering in the liquid. The study also shows that damping of the plasmon excitations in liquidAl is faster compared to solidAl due to electron-phonon interactions and/or Anderson localization of electrons.